1. Field of the Invention
The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile machine, or the like for forming an image constituted by a developing agent or agents and a combination machine combining these respective functions. More particularly, the invention concerns an image forming apparatus capable of improving convenience at the time of maintenance or various handling of such as a collection container accommodating a collecting developing agent which is to be collected among the developing agents used in the image formation.
2. Description of the Related Art
In an image forming apparatus for forming an image constituted by a developing agent or agents by adopting the electrophotographic process or the like, basic image formation is mainly effected in the following manner, and part of the developing agent used in the image formation is disused and is collected.
Namely, after an electrostatic latent image corresponding to predetermined image information is formed on an image carrier such as a photoconductor drum, the electrostatic latent image is developed by a developing agent such as a two-component developing agent, thereby forming a developing agent image (actually, a toner image constituted by a toner component). Subsequently, that developing agent image is transferred onto predetermined recording paper directly or indirectly through an intermediate transfer unit such as an intermediate transfer belt, and is then subjected to fixation. Image formation is thereby effected. In a case where not a monochrome image (mainly black image) but a color image which is formed by superposing monochrome developing agent images of a plurality of colors is formed as the image, the above-described development process and the development-agent-image transfer process are similarly repeated by the number of the monochrome development agent images required for forming that color image.
At the time of this image formation, an untransferred developing agent (mainly a toner component) or the like, which fails to be properly transferred onto a transfer destination, occurs at the time of transfer of the developing agent image, such as during primary transfer from the image carrier to the recording paper or the intermediate transfer unit, or during secondary transfer from the intermediate transfer unit to the recording paper. After such an untransferred developing agent is removed from the image carrier, the intermediate transfer unit, or the like by a cleaning device, the untransferred developing agent is collected in a collection container. In addition, in the case where the above-described color image is formed as the image, a plurality of image carriers such as the aforementioned photoconductor drums, and developing agent image of predetermined colors are respectively formed on the image carriers and are transferred onto the recording paper. Alternatively, an intermediate transfer system is frequently adopted in which a plurality of monochrome developing agent images formed on a single or a plurality of image carriers are superposed on the intermediate transfer unit, and these monochrome developing agent images are then collectively transferred onto the recording paper. However, in such a case, portions of occurrence of the collecting developing agents to be collected increase. Incidentally, in this case where the portions of occurrence of the collecting developing agents increase, it is generally necessary to cope with the case by increasing the number of transporting parts for transporting the collecting developing agents from the portions of occurrence of the collecting developing agents to the accommodating container, or by increasing the number of collection containers for accommodating the collecting developing agents.
In the image forming apparatus in which such a collecting developing agent is collected in a collection container, it is necessary to perform maintenance operation in which when the collecting developing agent to be collected in the collection container has become full, such a collection container is removed from an apparatus body and is then replaced with a new collection container, and the new collection container is mounted in the apparatus body.
However, in a case where a plurality of such collection containers are installed at a plurality of portions within the apparatus body, the replacement operation of those collection containers is required by the number of the collection containers, so that the maintenance operation becomes troublesome.
In a case where, for example, a so-called trickle development system is adopted as the development system, such a troublesome aspect is exacerbated since the number of parts of occurrence of the collecting developing agents further increases as developing devices adopting that development system correspond to the portions (parts) where the collecting developing agents occur. The trickle development system is a development system whereby, as a development system using a two-component developing agent whose principal components are toner and carrier, the two-component developing agent is replenished to the developing device slightly excessively, and a rather old developing agent stagnating in that developing device is mainly caused to overflow to outside the device as an excess developing agent and is collected. This ensures that the developing device is kept in a state of accommodating as much new developing agent as possible, so as to stabilize the development performance.
In contrast, as image forming apparatuses having a plurality of portions where the collecting developing agents occur such as cleaning devices, image forming apparatuses have conventionally been proposed which are constructed such that waste toner (collecting developing agent) collected by a plurality of cleaning devices is adapted to be collectively accommodated in a single collection container, for the purpose of simplifying the maintenance operation of the collection container for collecting that collecting developing agent and its mounting operation (e.g., refer to JP-A-9-325662, JP-A-10-153933 and JP-B-2912073). JP-A-9-325662 also discloses a technique of adopting a structure in which the single collection container is directly engaged with waste toner discharge portions of a plurality of cleaning devices.
JP-A-9-325662 (claim 6, paragraphs [0007] and [0043], FIG. 1, FIG. 4), JP-A-10-153933 (claim 1, paragraphs [0014] and [0035], FIG. 1) and JP-B-2912073 (paragraphs [0006] and [0039], FIG. 1) are referred to as related arts.
However, the following problems are encountered with the above-described image forming apparatus in which the collecting developing agents occurring from the plurality of parts of occurrence of the collecting developing agents are collectively accommodated in the single collection container.
Namely, in such an image forming apparatus, in a case where replacement parts requiring replacement at predetermined timings in view of useful life or the like (e.g., image carriers, an intermediate transfer unit, and developing devices) are removably mounted in the apparatus body, it has been necessary to separately perform the operation of replacing the aforementioned collection container in addition to the operation of replacing those replacement parts. For this reason, troublesome operation is inconveniently imposed on the user of such an image forming apparatus at the time of maintenance and handling of that collection container and the like.
In addition, since the collection container collectively accommodates the collecting developing agents from the plurality of parts of occurrence of the collecting developing agents, its capacity is required to a certain extent, so that the collection container tends to become large in size. From the viewpoint of making it possible to facilitate the mounting/removing replacement of such a large-size collection container, the collection container is frequently installed on an accessible one side surface side of the apparatus body. In this case, the apparatus body can also become large-sized by the portion in which its installation space is secured. This fact becomes a disadvantageous factor in rendering the image forming apparatus compact. In addition, in the event that a collection container having a small capacity is used, the collection container is filled up in a relatively short time cycle, and its replacement frequency becomes large, so that there is a possibility of frequently repeating the above-described troublesome maintenance operation.